Access Control: Least Privilege and Access Revocation

Guest blog courtesy of CYRISMA.

Access control forms the foundation of zero-trust security and effective data governance, helping organizations protect their sensitive information and minimize the risk of a breach. It involves policies, processes, and technologies designed to ensure that only authorized individuals or systems can access specific data, systems, networks, or physical spaces.

One of the fundamental principles associated with access control is the Principle of Least Privilege (PoLP), which dictates that users should have only the minimum level of access necessary to perform their tasks. While granting appropriate access to employees to be effective at their jobs is crucial, revoking access at the right time is equally important to ensure that your data remains secure. In this post, we touch briefly upon least-privilege access and discuss the best practices for access revocation when users no longer need a resource.

The Principle of Least Privilege (PoLP)

The Principle of Least Privilege is a fundamental security concept that dictates users, systems, or processes should have the minimum level of access necessary to perform their assigned tasks—and no more. This approach reduces the risk of accidental or malicious misuse of access rights, minimizing the potential impact of security breaches.

Key Aspects of PoLP

Restricted Access: Only the permissions required for a specific role or task are granted.

Temporary Access: Elevated access is provided only for the duration of the task and then revoked.

Segmentation: Different users or systems are isolated to prevent unauthorized lateral movement within an environment.

Continuous Monitoring: Access rights are reviewed and adjusted regularly to ensure alignment with current roles and responsibilities.

PoLP and Admin-level/Privileged Access

Admin or privileged access refers to higher-level permissions that allow users to perform critical actions, such as:

Installing or modifying software.

Accessing sensitive data.

Changing system configurations.

Managing user accounts and permissions.

Admin-level access is inherently powerful, and misuse—whether accidental or intentional—can lead to significant security and operational risks. Applying PoLP to privileged access ensures that these elevated permissions are tightly controlled.

At what point should organizations revoke access to protected resources?

One of the critical steps involved in strong access control and implementing PoLP is revoking access to sensitive data or resources as soon as the business need is met, or it is determined that the user – whether an employee or third-party – should no longer have access.

Access should be revoked at specific points to ensure data security, prevent unauthorized use, and maintain compliance with governance policies.

When an Employee Leaves the Organization

Why: Departing employees no longer have a legitimate need to access organizational resources. Delayed revocation can lead to intentional or accidental misuse of data.

Action: Immediately revoke access to all systems, networks, and data upon resignation, termination, or retirement.

When Job Roles Change

Why: Role changes may alter the need for access to specific data or systems. Continuing access to unnecessary resources violates the principle of least privilege.

Action: Adjust or revoke access as part of onboarding for a new role or transfer to another department.

After Contract Termination or Project Completion (for Third Parties)

Why: Vendors, contractors, and temporary workers should not retain access after their engagement ends to prevent unauthorized use.

Action: Revoke access upon completion of the contract or project, ensuring all accounts and credentials are disabled.

When Access is Misused or a Security Breach Occurs

Why: Misuse of access or involvement in a security incident can compromise sensitive data or systems. Immediate revocation prevents further damage.

Action: Revoke access for individuals under investigation or those found violating policies, and escalate for further review if necessary.

When Access is Unused for an Extended Period

Why: Dormant accounts pose a security risk, as they can be exploited by attackers without detection.

Action: Implement automated checks to deactivate accounts that remain unused for a predefined duration.

Upon Detection of Policy Violations

Why: Users who breach security or compliance policies may pose a risk to data integrity and availability.

Action: Revoke access immediately to limit potential harm and initiate corrective or disciplinary actions.

Best Practices for Access Revocation

Automated Deactivation: Use identity and access management (IAM) tools to automate access revocation during employee offboarding or role changes.

Regular Audits: Conduct periodic reviews of user access to ensure it aligns with current roles and responsibilities.

Clear Governance Policies: Define revocation procedures in access control and governance policies to ensure consistent enforcement.

Immediate Response: Act promptly to revoke access when necessary, minimizing the window of vulnerability.

By revoking access at the right time, organizations mitigate the risks associated with unauthorized access while also strengthening their data governance. Strong access settings cannot be on set-and-forget mode and need regular assessment and checks to prevent configuration drift and unexpected data exposure. Ensure that you have concrete access revocation policies that are rigorously implemented to keep sensitive data secure at all times.

How CYRISMA can help

CYRISMA’s cyber risk management platform includes multiple tools and assessments to help you implement strong access controls and assess existing controls for security and compliance.

Run secure configuration scans on client systems to check OS settings against the CIS Benchmarks or DISA STIGs and mitigate risk.

Use CYRISMA’s data scans to find sensitive data. Mark out your clients’ protect surface to help with micro-segmentation and applying strong access controls to critical resources.

Monitor Active Directory (both on-prem and Azure) for active accounts, disabled accounts, user activity status, etc. and get a centralized view of your clients’ AD environments so you can make the appropriate changes to strengthen security, and help them remain compliant with GRC standards.

Conduct compliance assessments with multiple best practice frameworks and regulatory standards.

Book a demo for a first-hand look and information about our year-end offer!